In that tutorial, the model was aligned with respect to global axes in such a way that S33 corresponded to normal stress at the point of contact predicted by the Hertz formula.
If you want to transform the results to another coordinate system, you could also try adding the *ORIENTATION keyword and adding the GLOBAL=NO parameter to *EL FILE (via the Keyword Editor or after exporting the input file) since for *EL FILE we read in ccx manual:
With the parameter GLOBAL you tell the program whether you would like the results in the global rectangular coordinate system or in the local element system. If an *ORIENTATION card is applied to the element at stake, this card defines the local system. If no *ORIENTATION card is applied to the element, the local system coincides with the global rectangular system unless for shell elements […]. Default value for the GLOBAL parameter is GLOBAL=YES, which means that the results are stored in the global system […]. If you prefer the results in the local system, specify GLOBAL=NO.
